Bridge multi-modal vortex vibration simulation device and design method thereof

Abstract

The application discloses a bridge multi-modal vortex vibration simulation device, which comprises a support frame, a limiting mechanism, a continuous beam and an elastic component. The limiting mechanism comprises two limiting components which are oppositely arranged along a first direction, each limiting component comprises a support plate, two bearing seats which are oppositely arranged on the support plate along a second direction and a support shaft, and the support plate is arranged on the support frame. The continuous beam comprises a core beam and an outer cover which is wrapped outside the core beam, the core beam extends along the first direction, and each end of the core beam penetrates through a corresponding support shaft. The elastic component comprises a plurality of springs which are arranged at intervals along the first direction, the upper end of the spring is connected to the support frame, the lower end of the spring is connected with a steel wire, the steel wire penetrates into the outer cover and is connected with the core beam. The second direction is perpendicular to the first direction. The application also discloses a design method of the bridge multi-modal vortex vibration simulation device. By adjusting the spring stiffness and position, the frequency characteristics and vibration mode characteristics of the simulation device are kept highly consistent with the real bridge, and then the precise simulation of the bridge multi-modal vortex vibration is realized.

Description

Technical Field

[0001] This invention relates to the field of bridge engineering technology, and in particular to a bridge multimodal vortex-induced vibration simulation device and its design method. Background Technology

[0002] Bridges, as core infrastructure of transportation networks, are crucial for facilitating the cross-regional flow of people and the efficient transfer of goods. Their long-term stable service not only directly affects the smooth flow of regional traffic but also plays an irreplaceable role in ensuring public safety and promoting economic and social development. Throughout their long service life, bridges must continuously withstand various external loads, among which wind load is one of the main factors inducing bridge structural vibration.

[0003] Vortex-induced vibration (VIV), a typical form of vibration induced by wind load, is characterized by its ease of triggering at low wind speeds, long duration, and wide impact range. Its generation mechanism is as follows: when airflow passes over the surface of a bridge's main girder, periodically alternating vortices are formed on both sides of the girder. These vortices generate periodically changing aerodynamic forces on the main girder. When the frequency of these aerodynamic forces approaches the natural frequency of the bridge structure, structural resonance occurs, i.e., VIV. For long-span cable-stayed bridges, due to their complex structural system and dense frequency distribution, VIV often exhibits characteristics of multiple potential vibration modes. Under the coupling effect of multimodal VIV, intense modal competition occurs between different modes, and the excitation frequencies of each mode of VIV differ significantly. This multimodal coupling and competition effect directly affects the vibration response of the bridge structure and is a core element in assessing the risk of bridge VIV. Therefore, accurately simulating the excitation frequency and vibration amplitude of bridges under different modes is of vital engineering significance and urgent practical need for scientifically assessing the impact of vortex-induced vibration on bridge structures, optimizing bridge anti-vortex-induced vibration design, and ensuring the long-term safe service of bridges.

[0004] Currently, the single-degree-of-freedom segmental model is widely used in the field of bridge vortex-induced vibration simulation. However, this model has obvious technical limitations: 1. Limited modal simulation dimension: The single-degree-of-freedom segmental model can only simulate a single vibration mode of the main girder of the bridge (such as simple vertical bending vibration or simple torsional vibration), and cannot reproduce the multi-modal coupled vortex-induced vibration phenomenon that is common in actual long-span bridges. The competition between different modes of vortex-induced vibration under multi-modal coupling is a key factor in determining the risk level of bridge vortex-induced vibration. The lack of this core feature makes it difficult for this model to capture the real risk situation of vortex-induced vibration in actual bridges; 2. Low structural response fidelity: In order to achieve vibration simulation of a single degree of freedom, this model greatly simplifies the actual structural stiffness distribution of the main girder of the bridge, and also idealizes the boundary conditions, retaining only the vibration degree of freedom in a single direction. This simplification ignores the complex constraint relationships and synergistic mechanisms between different degrees of freedom of the main girder of the bridge. As a result, the simulated vortex-induced vibration amplitude, vibration frequency and vibration attenuation law have significant deviations from the actual response of the actual bridge. It is difficult to accurately reflect the true stress state and vibration characteristics of the structure under vortex-induced vibration, and cannot provide reliable technical support for the vortex-induced vibration resistance design of bridges. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a bridge multimodal vortex-induced vibration simulation device and its design method.

[0006] To achieve the above objectives, an embodiment of the present invention provides the following technical solution:

[0007] A bridge multimodal vortex-induced vibration simulation device, comprising:

[0008] Support frame;

[0009] A limiting mechanism includes two limiting components arranged opposite to each other along a first direction. Each limiting component includes a support plate, two bearing seats arranged opposite to each other along a second direction on the support plate, and a support shaft passing through the two bearing seats. The support plate is disposed on the support frame.

[0010] A continuous beam, the continuous beam comprising a core beam and an outer covering over the core beam, the core beam extending along the first direction, each end of the core beam passing through a corresponding support shaft;

[0011] The elastic component includes a plurality of springs spaced apart along the first direction, the upper end of each spring being connected to the support frame, and the lower end of each spring being connected to a steel wire, the steel wire extending into the outer garment and connected to the core beam;

[0012] The second direction is perpendicular to the first direction.

[0013] As a further improvement of the present invention, the support frame includes two upright assemblies arranged opposite to each other along the first direction, an upper horizontal bar assembly and a lower horizontal bar assembly connecting the two upright assemblies, the support plate being connected to the upright assemblies, and the upper end of the spring being connected to the upper horizontal bar assembly.

[0014] As a further improvement of the present invention, the upright assembly includes a base rod extending along the second direction and two uprights disposed opposite to each other on the base rod, and the support plate is respectively connected to the two uprights.

[0015] As a further improvement of the present invention, a first reinforcing rod is connected between each of the uprights and the base rod, the first reinforcing rod being inclined, and a second reinforcing rod is connected between the two uprights of each upright assembly, the second reinforcing rod being located above the support plate.

[0016] As a further improvement of the present invention, the upper horizontal bar assembly includes two upper horizontal bars arranged opposite to each other along the second direction, the upper horizontal bars being connected to the vertical bar, and a plurality of horizontal suspension rods being connected between the two upper horizontal bars, the upper end of the spring being connected to the horizontal suspension rods.

[0017] As a further improvement of the present invention, the lower horizontal bar assembly includes two lower horizontal bars arranged opposite each other along the second direction, the lower horizontal bars being connected to the bottom bar, and a plurality of third reinforcing bars being connected between the two lower horizontal bars.

[0018] A design method for a bridge multimodal vortex-induced vibration simulation device, used in the aforementioned bridge multimodal vortex-induced vibration simulation device, includes the following steps:

[0019] (1) Define the design input parameters, including the structural parameters and modal parameters of the target bridge, and the number of modes to be simulated. The structural parameters include the length, cross-sectional dimensions and material properties of the main beam, and the modal parameters include the natural frequencies and mode shapes of each order.

[0020] (2) Determine the basic design parameters of the simulation device, including the length, cross-sectional dimensions and material properties of the continuous beam, as well as the initial number of springs;

[0021] (3) Set optimization parameters, including the section bending stiffness EI of the continuous beam and the position of the spring. ;

[0022] (4) Based on the dynamic control equations, the mode shape expression is obtained by solving;

[0023] (5) Calculate the actual parameters of the simulation device, including the stiffness of each spring. and the corresponding mode shape ;

[0024] (6) Perform accuracy verification to determine whether the deviation between the simulated mode shape and the target mode shape meets the requirements. If the deviation meets the requirements, the design is completed; if the deviation does not meet the requirements, return to step (3) and adjust the optimization parameters EI and Recalculate and verify until the accuracy requirements are met.

[0025] As a further improvement of the present invention, in step (4), the dynamic control equation is:

[0026]

[0027] in, The equivalent mass per unit length of a continuous beam. For different positions along the length of the continuous beam Different times The vertical displacement, For the flexural stiffness of the continuous beam section, For the first The stiffness of the spring constraint. Let be the position of the i-th spring along its length. For the Dirac function, only at the constraint position The third item, which takes effect at the point of application, represents the overall reaction force of the constraint on the continuous beam, reflecting the influence of local constraints on vibration.

[0028] As a further improvement of the present invention, in step (4), the mode shape expression is:

[0029]

[0030] in, , , , These are the four mechanical boundary quantities of the continuous beam: displacement at the left end, section rotation angle, bending moment, and shear force. For dimensionless axial coordinates, These are dimensionless frequency characteristic parameters. The height of the continuous beam. For the first Spring stiffness, For the first The axial position of the spring.

[0031] As a further improvement of the present invention, in step (6), verification ;in, , The number of iterations calculated in the current iteration is the first one. Mode shape function, For the target / theoretical standard Mode shape, The L2 norm is used to quantify the overall deviation between the current mode shape and the target mode shape. This is a pre-set convergence accuracy threshold.

[0032] The beneficial effects of this invention are:

[0033] (1) The present invention forms a simulation device through the cooperation of a support frame, a limiting mechanism, a continuous beam, and elastic components. By flexibly changing the stiffness parameters and installation position of the springs, the vibration frequency and mode shape of the continuous beam can be precisely controlled, realizing the accurate simulation of multi-mode vortex-induced vibration. This significantly improves the accuracy and practicality of bridge vortex-induced vibration simulation and provides a scientific basis for bridge anti-vortex-induced vibration design. This structure can adapt to the bridge simulation requirements of different parameters without modifying the main structure of the continuous beam. It has the advantages of flexibility, versatility, and economy, and solves the problems of poor adaptability and high adjustment cost of traditional models.

[0034] (2) This invention breaks through the single degree of freedom limitation of traditional segmental models, realizes the synchronous simulation of multi-mode vortex vibration, accurately captures the energy transfer process and interaction law between different modes; accurately simulates the modal parameters of the actual bridge structure, including the natural frequency and mode shape characteristics of each mode, and truly reproduces the multi-mode competition effect of vortex vibration, making the simulation results more consistent with the actual working conditions of the actual bridge; it takes into account the high precision and efficiency of the simulation, ensuring that while improving the accuracy of the simulation, it simplifies the operation process, improves the simulation efficiency, and reduces the cost of engineering applications.

[0035] (3) The design method of this invention breaks through the simplification assumptions of traditional models on structures, and can accurately characterize the influence of local constraints on overall vibration, providing a solid theoretical basis for the accurate simulation of multimodal vortex vibration.

[0036] (4) The present invention uses partial differential equations with Dirac function to construct a dynamic model. Combined with the actual boundary conditions of the main beam, the bridge vibration mode expressions under different modes are accurately obtained through rigorous mechanical derivation.

[0037] (5) The present invention has good adaptability and can be applied to bridges with different cross-sectional forms and different structural parameters. It provides a universal and reliable technical means for the anti-vortex vibration safety assessment and design optimization of various types of bridges, and fully guarantees the anti-vortex vibration safety performance of bridges. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 This is a schematic diagram of the simulation device according to a preferred embodiment of the present invention;

[0040] Figure 2 for Figure 1 Enlarged diagram of A in the middle;

[0041] Figure 3 This is a schematic diagram of the mechanical structure of the simulation device according to a preferred embodiment of the present invention;

[0042] Figure 4 A flowchart illustrating the design method of a preferred embodiment of the present invention;

[0043] In the diagram: 1. Support frame, 11. Upright assembly, 111. Base rod, 112. Upright, 113. First reinforcing rod, 114. Second reinforcing rod, 12. Upper horizontal rod assembly, 121. Upper horizontal rod, 122. Horizontal hanger, 13. Lower horizontal rod assembly, 131. Lower horizontal rod, 132. Third reinforcing rod, 2. Continuous beam, 21. Core beam, 22. Outer covering, 3. Limiting assembly, 31. Support plate, 32. Bearing seat, 33. Support shaft, 4. Spring, 5. Steel wire. Detailed Implementation

[0044] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0045] Please see Figure 1 , Figure 2 This application discloses a bridge multimodal vortex-induced vibration simulation device, including a support frame 1, a limiting mechanism, a continuous beam 2, and elastic components. The support frame 1 is used to position the simulation device in a wind tunnel test chamber. The limiting mechanism includes two limiting components 3 arranged opposite each other along a first direction. Each limiting component 3 includes a support plate 31, two bearing seats 32 arranged opposite each other along a second direction on the support plate 31, and a support shaft 33 passing between the two bearing seats 32. The support plate 31 is disposed on the support frame 1. The continuous beam 2 includes a core beam 21 and an outer casing 22 covering the core beam 21. The core beam 21 extends along the first direction, and each end of the core beam 21 passes through a corresponding support shaft 33. The elastic component includes a plurality of springs 4 arranged at intervals along the first direction. The upper end of the springs 4 is connected to the support frame 1, and the lower end of the springs 4 is connected to a steel wire 5. The steel wire 5 extends into the outer casing 22 and is connected to the core beam 21. The second direction is perpendicular to the first direction. The first direction is... Figure 1 The X-axis direction, the second direction is Figure 1The Y-axis direction in the diagram.

[0046] The core beam 21 provides the stiffness of the continuous beam 2, the outer casing 22 provides the aerodynamic shape of the continuous beam 2, the limiting component 3 acts as a boundary condition, and the support shaft 33 can rotate relative to the bearing seat 32, facilitating the movement of the core beam 21 and controlling the degree of freedom of the boundary conditions. The length direction of the continuous beam 2 is the same as the first direction. In this invention, several springs 4 are installed at different length positions of the continuous beam 2, and the stiffness of each spring 4 can be independently adjusted according to simulation requirements. By rationally arranging the installation positions of each spring 4 and precisely controlling the stiffness parameters of each spring 4, the vibration frequency and mode shape of the simulation device can approximate the structural characteristics of a real bridge to the greatest extent possible, thereby achieving accurate simulation of multimodal vortex-induced vibration. Preferably, the core beam 21 is made of steel or aluminum. Preferably, the outer casing 22 is made of OBS, wood, or aluminum.

[0047] In this embodiment, the support frame 1 includes two upright pole assemblies 11 arranged opposite to each other along a first direction, an upper horizontal pole assembly 12 and a lower horizontal pole assembly 13 connecting the two upright pole assemblies 11, a support plate 31 connected to the upright pole assembly 11, and the upper end of the spring 4 connected to the upper horizontal pole assembly 12.

[0048] The preferred upright assembly 11 includes a base rod 111 extending along a second direction, two uprights 112 disposed opposite to each other on the base rod 111, and a support plate 31 connected to the two uprights 112 respectively.

[0049] To improve the stability of the upright assembly 11, it is preferable that each upright 112 is connected to the base rod 111 with a first reinforcing rod 113, the first reinforcing rod 113 is inclined, and a second reinforcing rod 114 is connected between the two uprights 112 of each upright assembly 11, the second reinforcing rod 114 being located above the support plate 31.

[0050] To improve the stability of the upper horizontal bar assembly 12 and facilitate a stable connection to the spring 4, the upper horizontal bar assembly 12 preferably includes two upper horizontal bars 121 arranged opposite each other along the second direction. The upper horizontal bars 121 are connected to the upright bar 112, and a plurality of horizontal hangers 122 are connected between the two upper horizontal bars 121. The upper end of the spring 4 is connected to the horizontal hangers 122.

[0051] To improve the stability of the lower horizontal bar assembly 13, the lower horizontal bar assembly 13 preferably includes two lower horizontal bars 131 arranged opposite each other along the second direction. The lower horizontal bars 131 are connected to the bottom bar 111, and a plurality of third reinforcing bars 132 are connected between the two lower horizontal bars 131.

[0052] like Figure 1As shown, two springs 4 are installed at 1 / 3 and 2 / 3 of the continuous beam 2. By adjusting the stiffness of the springs 4, the frequencies of multiple modes can be changed. The stiffness of the springs 4 can be adjusted by replacing them with new springs.

[0053] The mechanical schematic diagram of the simulation device in this embodiment is shown below. Figure 3 As shown in the figure, the length parameters of continuous beam 2 are clearly displayed. equivalent mass per unit length Section bending stiffness and the stiffness parameters of each spring 4 , , and installation location parameters , , The figure also shows the first-order vibration mode. Second-order vibration mode and third-order vibration modes The distribution characteristics intuitively reflect the vibration mode of the continuous beam under different modes, providing a clear visual basis for subsequent mechanical analysis and parameter optimization.

[0054] Please see Figure 4 This application also discloses a design method for a bridge multimodal vortex-induced vibration simulation device, including the following steps:

[0055] (1) Define the design input parameters, including the structural parameters and modal parameters of the target bridge, and the number of modes M to be simulated. The structural parameters include the length, cross-sectional dimensions and material properties of the main beam, and the modal parameters include the natural frequencies of each order. , vibration shape .

[0056] (2) Determine the basic design parameters of the simulation device, including the length, cross-sectional dimensions and material properties of the continuous beam 2, and the initial number N of springs 4.

[0057] Based on the structural parameters of the target bridge, the length, cross-sectional dimensions, and material properties of the continuous beam are determined by scaling.

[0058] (3) Set optimization parameters, including the section bending stiffness EI of continuous beam 2 and the position of the spring. .

[0059] Set EI and according to the desired number of vibration modes. .

[0060] (4) Based on the dynamic control equation, the mode shape expression is obtained by solving.

[0061] Preferably, the dynamic governing equations are:

[0062]

[0063] in, The equivalent mass per unit length of a continuous beam. For different positions along the length of the continuous beam Different times The vertical displacement, For the flexural stiffness of the continuous beam section, For the first The stiffness of the spring constraint. For the first The position of the spring along its length. For the Dirac function, only at the constraint position The third item, which takes effect at the point of application, represents the overall reaction force of the constraint on the continuous beam, reflecting the influence of local constraints on vibration.

[0064] The mode shape expression is:

[0065]

[0066] in, , , , These are the four mechanical boundary quantities of the continuous beam: displacement at the left end, section rotation angle, bending moment, and shear force. For dimensionless axial coordinates, These are dimensionless frequency characteristic parameters. The height of the continuous beam. For the first Spring stiffness, For the first The axial position of the spring.

[0067] (5) Calculate the actual parameters of the simulation device, including the stiffness of each spring. and the corresponding mode shape .

[0068] (6) Perform accuracy verification to determine whether the deviation between the simulated mode shape and the target mode shape meets the requirements. If the deviation meets the requirements, the design is completed; if the deviation does not meet the requirements, return to step (3) and adjust the optimization parameters EI and Recalculate and verify until the accuracy requirements are met.

[0069] Preferably, the accuracy verification performed in step (6) is a verification ;in, , The number of iterations calculated in the current iteration is the first one. Mode shape function, For the target / theoretical standard Mode shape, The L2 norm is used to quantify the overall deviation between the current mode shape and the target mode shape. This is a pre-set convergence accuracy threshold.

[0070] This invention first obtains the structural and modal parameters of the target bridge, and then designs the basic dimensions and materials of the continuous beam 2 based on these parameters. Based on vibration dynamics theory, the dynamic control equation of the continuous beam is established to accurately describe the vibration response law of the simulation device. Then, the optimal installation position and corresponding stiffness value of the spring 4 are determined by the mode shape expression optimization algorithm. By adjusting the stiffness and position of the spring 4, the frequency characteristics and mode shape characteristics of the simulation device are kept highly consistent with those of the real bridge, thereby achieving accurate simulation of multimodal vortex-induced vibration of the bridge.

[0071] To further illustrate the design method of the bridge multimodal vortex vibration simulation device of the present invention, the following specific embodiments are provided.

[0072] Example 1

[0073] Basic parameters of continuous beam model 2: length L=11.79m, section bending stiffness EI=128240.77Nm², equivalent mass per unit length m=60kg / m;

[0074] Spring 4 parameters: Two springs 4 are used, spaced apart along the length of the continuous beam 2; the stiffness of each spring 4 is 57656.08 N / m; the installation positions of springs 4 are 4.88 m and 6.96 m from one end of the continuous beam 2, respectively. =4.88m, =6.96m.

[0075] Simulation results: The first-order frequency of the continuous beam 2 in the simulation device is 7.33Hz and the second-order frequency is 8.77Hz; the first-order mode shape is a positive symmetric vertical bending mode shape and the second-order mode shape is an antisymmetric vertical bending mode shape shape. The deviations of each modal parameter from the modal parameters of the target bridge are all less than 0.5%, which meets the engineering simulation accuracy requirements.

[0076] Example 2

[0077] Basic parameters of continuous beam model 2: length L=15.0m, section bending stiffness EI=185600.0Nm², equivalent mass per unit length m=75kg / m;

[0078] Spring 4 parameters: Three springs 4 are used, and their installation positions are as follows: =3.5m =7.5m =11.5m; the stiffness of spring 4 are respectively =48200.0 N / m =62500.0 N / m =48200.0 N / m;

[0079] Simulation results: The first-order frequency of the simulation device is 5.21Hz, the second-order frequency is 6.89Hz, and the third-order frequency is 9.35Hz; the corresponding vibration modes are the first-order positive symmetric vertical bending, the second-order antisymmetric vertical bending, and the third-order positive symmetric vertical bending, respectively. The deviations of the modal parameters of each order from the modal parameters of the target bridge are all less than 0.8%, realizing the accurate simulation of three-mode vortex-induced vibration.

[0080] Example 3

[0081] Basic parameters of continuous beam model 2: length L=10.0m, section bending stiffness EI=98600.0Nm², equivalent mass per unit length m=52kg / m;

[0082] Spring 4 parameters: Two springs 4 are used, and the installation position is as follows. =3.0m =7.0m; the stiffness of spring 4 are respectively =51300.0 N / m =51300.0 N / m;

[0083] Simulation results: The first-order frequency of the simulation device is 8.42Hz and the second-order frequency is 10.15Hz; the first-order vibration mode is positive symmetric vertical bending and the second-order vibration mode is antisymmetric vertical bending. The deviations of the modal parameters of each order from the modal parameters of the target bridge are all less than 0.6%, which makes it suitable for multimodal vortex vibration simulation of small and medium span bridges.

[0084] Through actual simulation verification, each embodiment can accurately simulate the multimodal vortex-induced vibration of the target bridge, fully demonstrating the feasibility and effectiveness of the technical solution of the present invention.

[0085] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0086] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A bridge multimodal vortex-induced vibration simulation device, characterized in that, include: Support frame; A limiting mechanism includes two limiting components arranged opposite to each other along a first direction. Each limiting component includes a support plate, two bearing seats arranged opposite to each other along a second direction on the support plate, and a support shaft passing through the two bearing seats. The support plate is disposed on the support frame. A continuous beam, the continuous beam comprising a core beam and an outer covering over the core beam, the core beam extending along the first direction, each end of the core beam passing through a corresponding support shaft; The elastic component includes a plurality of springs spaced apart along the first direction, the upper end of each spring being connected to the support frame, and the lower end of each spring being connected to a steel wire, the steel wire extending into the outer garment and connected to the core beam; The second direction is perpendicular to the first direction.

2. The bridge multimodal vortex-induced vibration simulation device according to claim 1, characterized in that, The support frame includes two upright assemblies arranged opposite each other along the first direction, an upper horizontal bar assembly and a lower horizontal bar assembly connecting the two upright assemblies, a support plate connected to the upright assemblies, and the upper end of the spring connected to the upper horizontal bar assembly.

3. The bridge multimodal vortex-induced vibration simulation device according to claim 2, characterized in that, The upright assembly includes a base rod extending along the second direction and two uprights disposed opposite to each other on the base rod, with the support plate connected to the two uprights respectively.

4. The bridge multimodal vortex-induced vibration simulation device according to claim 3, characterized in that, Each of the uprights is connected to the base rod by a first reinforcing rod, the first reinforcing rod being inclined, and each of the two uprights of each upright assembly is connected by a second reinforcing rod, the second reinforcing rod being located above the support plate.

5. The bridge multimodal vortex-induced vibration simulation device according to claim 3, characterized in that, The upper horizontal bar assembly includes two upper horizontal bars arranged opposite each other along the second direction. The upper horizontal bars are connected to the vertical bar, and a plurality of horizontal suspension rods are connected between the two upper horizontal bars. The upper end of the spring is connected to the horizontal suspension rod.

6. The bridge multimodal vortex-induced vibration simulation device according to claim 3, characterized in that, The lower horizontal bar assembly includes two lower horizontal bars arranged opposite each other along the second direction. The lower horizontal bars are connected to the bottom bar, and a plurality of third reinforcing bars are connected between the two lower horizontal bars.

7. A design method for a bridge multimodal vortex-induced vibration simulation device, characterized in that, A bridge multimodal vortex-induced vibration simulation device as described in any one of claims 1-6, comprising the following steps: (1) Define the design input parameters, including the structural parameters and modal parameters of the target bridge, and the number of modes to be simulated. The structural parameters include the length, cross-sectional dimensions and material properties of the main beam, and the modal parameters include the natural frequencies and mode shapes of each order. (2) Determine the basic design parameters of the simulation device, including the length, cross-sectional dimensions and material properties of the continuous beam, as well as the initial number of springs; (3) Set optimization parameters, including the section bending stiffness EI of the continuous beam and the position of the spring. ; (4) Based on the dynamic control equations, the mode shape expression is obtained by solving; (5) Calculate the actual parameters of the simulation device, including the stiffness of each spring. and the corresponding mode shape ; (6) Perform accuracy verification to determine whether the deviation between the simulated mode shape and the target mode shape meets the requirements. If the deviation meets the requirements, the design is completed; if the deviation does not meet the requirements, return to step (3) and adjust the optimization parameters EI and Recalculate and verify until the accuracy requirements are met.

8. The design method of a bridge multimodal vortex-induced vibration simulation device according to claim 7, characterized in that, In step (4), the dynamic control equation is: in, The equivalent mass per unit length of a continuous beam. For different positions along the length of the continuous beam Different times The vertical displacement, For the flexural stiffness of the continuous beam section, For the first The stiffness of the spring constraint. For the first The position of the spring along its length. For the Dirac function, only at the constraint position The third item, which takes effect at the point of application, represents the overall reaction force of the constraint on the continuous beam, reflecting the influence of local constraints on vibration.

9. The design method of a bridge multimodal vortex-induced vibration simulation device according to claim 7, characterized in that, In step (4), the mode shape expression is: in, , , , These are the four mechanical boundary quantities of the continuous beam: displacement at the left end, section rotation angle, bending moment, and shear force. For dimensionless axial coordinates, These are dimensionless frequency characteristic parameters. The height of the continuous beam. For the first Spring stiffness, For the first The axial position of the spring.

10. The design method of a bridge multimodal vortex-induced vibration simulation device according to claim 7, characterized in that, In step (6), verification ;in, , The number of iterations calculated in the current iteration is the first one. Mode shape function, For the target / theoretical standard Mode shape, The L2 norm is used to quantify the overall deviation between the current mode shape and the target mode shape. This is a pre-set convergence accuracy threshold.

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